What mtb 26 in. conversion kit should I buy TODAY?

[s_c]

I hope this is in the right place, please move if not. And wow there is a wealth of knowledge here but forgive me I'm still lost and looking for specific input here.

I'm looking to convert one of my old mountain bikes to an e-bike. Typically 68mm bb, 135mm dropouts. I would like to do a smaller diameter rear hub motor and ideally still get a little oomph off the line. This would be a fun bike for zipping around. I (200lb, 6ft) currently have a knee injury so need to be able to get going without much pedaling. I do plan on recovering and would like to be able to do 30-32mph with pedaling hard. I can play with gearing to get a gear that I can pedal that high. I wanted regen braking as I enjoy it in my vehicle but I've let that go given my budget.

For power/price I was targeting 1500W at 52V, though I'm seeing this may not be the best metric to meet my goals. In early searches (I started this last year) seems to me I could get a cheap kit for low $200 (AliX, etc) and then batteries start at around $200, so $400 total. However, I'm reading these direct drive hubmotors will not provide much torque off the line and generally people are recommending to get higher quality components.

I came across this kit from calibike and appreciated the compactness of the rear hub but upon further inspection it seems it may not actually be a 1500W setup. It doesn't say that anywhere but it just seems like all motors that size offered elsewhere are lower wattage. And if I'm getting a lower wattage setup, I could probably pay less.

https://calibike.com/product/52v-1500w-37-mph-3-5kg-waterproof-easy-connect-e-bike-conversion-kit-complete/

Is this a good kit or will I be disappointed? This is more than I initially wanted to spend but if it was really a compact motor that put out 1500W and got up to 37 MPH I could potentially push the budget. Even if that were true, I'd imagine the acceleration would be poor given what I'm reading.

Say I am willing to spend about $375 on the kit. What are some great options available now or maybe soon if out of stock given my goals?

Also not opposed to buying a used kit so save $ if available. It's likely this be ridden hard and infrequently, and not needed for commuter reliability

Thanks for your consideration

 

[gromike]

That's a geared hub motor wheel you linked, and that's why it's a smaller diameter. I recently put a 500w geared hub motor on a bike, it gets fed up to a 1000w. Built it for a guy with COPD, so not much pedaling. It will go 28mph on the flat, and climbs well. Heat build up on long climbs can be a problem with geared hub motors. Where I ride there are short steep climbs, and I have not had a problem. It would best to have a motor (& controller) temp. sensor.

 

[99t4]

Need more info to give any useful suggestions:

• Range requirements
• Speed, and time at speed
• Hills? Steepness and length
• Wheel size
• Budget

Suggest you do not cheap out on the battery. Most do not live up to their advertised specs; many are outright dangerous.

 

[s_c]

@gromike I'm not opposed to geared motor, but would like to know what I'm getting motorwise and the one I was looking at doesn't seem to give all the info (i.e. peak power vs sustained). Use will be mostly flat with some hilly sections (typically no more than 1/2 mile) followed by downhill and flats

@99t4

Range - I of course would like 10 go 100 miles, but 20 would be sufficient. This is an area where I may look to get going at budget with smaller battery and upgrade in the future

Speed - Sustained speeds 23+, max speed 30+

Hills - Nothing major. 1/2 mile and not too steep, followed by downhill/flat

Wheel - 26!

Budget - Let's say we limit the kit to that $375

 

[amberwolf]

(EDIT: you posted the info above this post before I submitted this post but after I started typing it, so some of the next sentence doesn't apply....but I'm leaving it to complete the post and why the rest of what I posted matters.

Note that "not too steep" is not a useful datum for figuring out what system you need, as you can't calcuilate required power from that, or put that in the ebikes.ca simulators .

The battery is the most important part of your system, since it has to provide all the power for the system to do the job with, so while you can get a smaller capacity battery to start with, it has to be able to perform proportionally better than that bigger battery would, so it may not cost much less

*******

I would like to do a smaller diameter rear hub motor and ideally still get a little oomph off the line. This would be a fun bike for zipping around. I (200lb, 6ft) currently have a knee injury so need to be able to get going without much pedaling. I do plan on recovering and would like to be able to do 30-32mph with pedaling hard. I can play with gearing to get a gear that I can pedal that high. I wanted regen braking as I enjoy it in my vehicle but I've let that go given my budget.

What is the complete job the bike needs to do for you, under what specific riding conditions / terrain (hills, slopes, road types, etc) / weather (wind, breeze, rain, cold, hot, etc), and how far does it have to go under those conditions? Defining all of these things will help you pick a system that does what you need without spending more than you need to, and keeping you from being disappointed in the results.

Note that you should presume that pedalling will make no difference to system requirements for the speed you want; even if you were uninjured and fully capable. (it might make some, but typically not much compared to the motor system at those speeds).
You're probably better off making sure at least some of your gearing can work for you when there is no motor operating, for all terrains and weathers you'll be on, for times when something goes wrong.


If you want regen braking, you can only use a couple of the geared hubmotors, like GMAC; the rest are mechanically incapable unless you modify them. Otherwise you must use a DD hubmotor, or a freewheelless midrive system (which you'd probably have to build from scratch, or heavily modify OTS versions to remove their freewheels, and then take out your wheel's freewheel).

Regen in almost every system out there is simply on/off, and won't be anything like the experience in a car. To get that experience, you'll need a controller specifically designed to do variable regen braking, almost all of which are FOC controllers, like the Phaserunner from ebikes.ca. Some Fardriver, ASI, Votol, Sevcon, Kelly, etc. can do it too, but all of these have either crappy setup software, crappy support, crappy hardware, and/or ridiculous company policies on administrating and licensing your access to your own settings on your own hardware, and/or or setup hardware/software that costs about as much as the controller itself. VESC variants exist that can do it, but many of them are not well built or have other design/manufacturing issues you may have to work around.

Choosing the way you control that variable regen is another factor--almost no ebrake controls have variability, so you may need to DIY something that will work the way you need it to, or with your bike's brake hardware. Or use a system like Grin's that can use the common ebrake switch to turn on the braking mode of the controller, and then use the throttle to modulate braking, which is not intuitive and can cause problems in emergency braking if you depend on the regen to stop you.


The GMAC is a small diameter geared freewheel-less motor that can do the regen and the speeds you want, but it will be pretty noisy at those speeds, even in a 26-29" wheel. (at 20" it would probably sound like really big drill ).

There are silent DD's such as the Ultramotor (found only used on bikes like the old A2B Metro, and old Stromers) that are bigger diameter than GMAC, but smaller and lighter than the typical DD's. They are not designed for sustained high power usage, but can take peaks of 1500W+ for a few seconds at a time easily enough (I use two of them at those rates on SB Cruiser for quick acceleration).


Which motor you should choose depends first on how you want the bike to perform and for how long at a time, then on things like how big you would like it to be, etc. It won't do you much good to choose a small motor that can't actually do the job you want.

 

[gromike]

The kit you linked should work well for you, as I get that performance from 500w rated motors. The controller, of course, gives more power than the motor's nominal rating. You would need a battery rated at 30+ amps.

The geared hub bike I built cost a total of about $350. That was with a battery and a motor from a scrapped Adventon Pace 500,
me lacing the motor wheel (rim and spokes about $100), a new controller and display ($100), and tires and tubes ($150). The bicycle was harvested from a pile of free bike parts. I did splurge on good tires.

 

[s_c]

@amberwolf re hills: Most of my ride is flat, but there are some rolling hills. The most demanding part of the route has about 150 ft of elevation gain over 0.5 miles, which puts the average grade at around 5.7%. I was thinking this wouldn’t be a big driver of the lot selection but now agree we should get this right

You mention some really great options. GMAC and phaserunner seem amazing but out of the budget unfortunately. I’ve accepted I’m not gonna get regen on this build

My main use is adventuring to various beaches/restaurants. I have some friends with varying e-bikes from name-brand race mtbs to monster dual motor options and I’d like to be able to keep up and maybe even roast them sometimes but that might be out of the budget

That said it’s amazing how much ebike you get for the money when you buy a whole bike. I was thinking I’d be able to buy a big motor and good battery and slap them on a basic 90s hardtail and be faster but it is not looking like I’m going to get to do all that. By the time you get a decent kit decent battery it’s almost the same price. I’m sure their bikes use the cheapest stuff but still, the motors, big battery, wheels tires frame brakes and similar costs to just the conversion components. Anyway, I digress.. I like my vintage bikes and would love to convert one and bring something new to the crew.

@gromike thats excellent you were able to salvage parts like that and build a legit bike. I guess my question with this kit I linked is it just 500w AliX parts with hyped up description that I should buy for less and try out or is it a unique worthy offering?

 

[99t4]

I like my vintage bikes and would love to convert one and bring something new to the crew.

Nothing wrong with that and realize you will experience immense satisfaction riding it, much more than riding a pre-built.

Some folks fall into the "must make it perfect all at once, one and done" trap. For most, it is an evolutionary progression. First build is more of a learning experience (not always a mistake!) for future incremental upgrades.

 

[E-HP]

Just in case you didn't already press the order button, and are still in the deciding phase:

Either the RH212 fast wind direct drive, or the GMAC 8T geared will get you bumping up against 30mph when fully charged. Range is identical at 19 miles on a 52v 13Ah battery. Performance is pretty close too, with the direct drive surprisingly having the edge off the line. This assumes 242lb total weight and sitting upright while riding, and only 50W of contribution from your injured legs. Once your leg heals and you can pedal, you could hit 30 on a half/nominally charged battery and over that when fully charged.

You can change the total weight or capacity of the battery in the simulator to see what works for you. As modeled, the direct drive will never overheat on a 7% grade, but the geared hub will overheat in an hour, but given your description, you won't be riding 7% for an hour straight.

Note that when you ride faster, you tend to instinctively tuck down a bit in your riding position. If you are in the mountain bike tuck position in the simulator, you're exceeding 32mph with the direct drive, even on the half charged battery, and 31mph with no pedaling. Fully charged that's 32mph with no pedaling and almost 34mph with pedaling.

Motor Simulator - Tools

Our ebike motor simulator allows you to easily simulate the different performance characteristics of different ebike setups - with a wide selection of hub motors modeled, and the ability to add custom batteries and controllers and set a wide variety of vehicle parameters you'll be able to see...

ebikes.ca

These motors would be beyond your budget, but you could find a cheap kit with a fast wind 9C clone direct drive for pretty cheap.

Motor Simulator - Tools

Our ebike motor simulator allows you to easily simulate the different performance characteristics of different ebike setups - with a wide selection of hub motors modeled, and the ability to add custom batteries and controllers and set a wide variety of vehicle parameters you'll be able to see...

ebikes.ca

 

[s_c]

Some folks fall into the "must make it perfect all at once, one and done" trap

No kidding… this is fatal. I better come to a decision quick…

@E-HP thanks for the analysis. I’m tempted to stretch budget for GMAC but then I think about it and I’m like why am I gonna spend that much right now

I watched an old video by nerdoutjohnnie and I’m afraid I’m going to go middrive for this first ebike. It still stretches the budget but not as much. I really wanted to do hub drive but part of that initial decision was that hub drive kits were available for pretty cheap and try e middrive kits looked expensive. However in order to get something with a little torque on hub drive I actually have to spend more… and I still like the hub drive but it isn’t worth the extra money

Now looking into bf02 vs bbshd for price/performance

 

[E-HP]

Sounds good; it’s a one and done, so you get what you get. Maybe it will suit your riding best if you’re lucky. And that way you spread out the maintenance costs over the life of the bike.
Im too lazy to do ebike maintenance (or think about shifting when I get to an intersection lol). When I got my first cheap 1000w hub kit from eBay ($144) it did everything I wanted at the time, and I ended up riding it hundreds of miles per month, when I thought I’d just be only doing short leisure rides. I customized and upgraded it over time, doing a lot of testing before and after when choosing parts. It started out to be all that I wanted, and still is, but what I wanted changed the more I rode. Natural progression.
I’m actually about to build a mid drive myself (tsdz8), but it’s only for slower single track trails, but I don’t think it will see much pavement except riding to the trailhead. With lower miles, i figure I’ll be changing chains and sprockets less often than if it were my main bike. For normal trails, my direct drive works great since it’s silent so I can ride right next to deer or cattle without spooking them. When I ran regen, I had zero maintenance costs (never changed brake pads for years). I really miss that. I have a lot of hills, so change pads a few times a year now, but not much hassle with hydraulic calipers. With regen, my maintenance consisted of changing tires.
My build thread is in my signature if you want to see an example of the progression or cost breakdown. There’s a draft newbie faq in my signature with some info and a lot of links if you’re still in the deciding stage. Truth is, it’s better to just get something and start having fun. As long as you have assist, you’ll be out riding thousands of miles before you know it, and probably building a second bike anyway.

 

[s_c]

@E-HP This is brutal. Your build is inspiring... you started with a cheapo kit as I had initially wanted to and got some good results, and have upgraded from there. I'll admit.. hearing your results takes me off the mid-drive again. I wouldn't have expected this but a fig factor for me is the appearance. I like the rear wheel motor... has a nice hot rod look and all is within the bike envelope. The mid-drive motor hanging off the bb is not really what I had in mind even though that's how motorcycles look.

Can I ask if you were going to buy a cheap rear hub kit today that would actually give a little torquiness and hill-climb ability, what would you go for? Is there anything that offers some torque that can do regen or is GMAC the only game in town for that?

Base bike may be a Mongoose ATB. One way I'm thinking to save money is to buy the hub motor itself and spokes and install it onto existing rear wheel to maintain that aesthetic. Other bike it could go on is a '93 Hard Rock Ultra.

 

[E-HP]

There are a lot of options for getting your foot in the door. Doing a quick Amazon search ("26" 1000W rear hub motor kit") on similar kits to the one I started with, are running more in the $220 range after shipping. Most of those 1000W direct drive 9C clone motors are the same, except for their speeds. In my case, although I was a newbie during my first build, I spent a lot of time reading here, so I didn't just get a kit solely based on the components, but looked for one with a motor that would likely give me enough torque to get up the hills. Generally speed and torque are a trade off, so the motor I got would only do 23mph on 52V, but had pretty good torque for hill climbing. There's not much info provided in the listings, but they will often include a top speed, that you can guess whether it's wound for faster speeds or for more torque, given the input voltage.
The kit allowed me to buy all the extra peripherals cheaper than buying them piece meal (PAS sensor, brake levers, etc.), so even though I chucked the kit controller and never used it it was still cheaper than buying components. I bought a sinewave KT (Kunteng) controller (because I wanted my bike to be silent) and display separately for the build.
The KT controllers have a smooth power delivery when using PAS or throttle in this power range, so that's what I got, and it worked great. So, at the time, my "kit" cost $144 plus around $80 for the KT components.
A kit that uses a KT sine wave controller would probably be ideal for getting you going, if you can find one. Otherwise you could just use a kit as-is and upgrade later. If I were doing my initial build over, I would have chosen a more flexible controller (some of their controllers can operate at different voltage levels, so I would have gotten one where I could up the voltage later), so if you go that route, keep that in mind so you have an upgrade path where you don't have to replace everything. My 1000W hub easily handled 2000W when climbing, and a lot more when I upgraded things later (using Statorade to keep it cool).

PS. there's nothing wrong with the kit you posted a link to. looks like it uses a KT controller too. it's a geared hub, so will make more noise than direct drive. But for the same money, you could probably do better.

 

[2old]

As above, my kit is of the $225 "9C" variety (30 amp controller) and 52V battery (about $400 from a US manufacturer) which easily exceeds 30 mph and has been reliable for the last couple of years. If you already have a good donor bike, something like this should suffice. I question whether the "375" kit will achieve 37 mph with a 25 amp controller.

 

[dgc]

Out of interest what size frame is it? I have always used TSDZ2(B)s on full suspension frames, get about 30mile range, but I am going to build a hard-tail to allow for a bigger battery with a TSDZ8 or rear hub motor, a bit short in leg so usually ride a small / medium frame, might even fit shorter 152mm / 160mm cranks. but also looking at a Specialized Epic M5 Comp FSR frame in good condition for £150.

 

[s_c]

@2old beautiful bike. you got the top end vintage specialized mtb there in an amazing color and good paint with simple fixed modern fork and fast tires. my hard rock is blushing. clean, this is similar to what i had in mind. Are you doing any regen? Do you have to adjust your riding for slower speeds to prevent overheating or just don't use the motor much those times?

@dgc you asking me or 2old? if me the mongoose atb is 21" and the hard rock ultra is 19". Neither is perfect for me on long drives but either will be acceptable once i've got the motor assisting. I love the maneuverability of the 19" but can get cramped on long hard rides and the atb geometry is just a little dated, i just need to raise the handlebars to cruise comfortably. I'll be higher than necessary but the view is nice up there

 

[2old]

Out of interest what size frame is it? I have always used TSDZ2(B)s on full suspension frames, get about 30mile range, but I am going to build a hard-tail to allow for a bigger battery with a TSDZ8 or rear hub motor, a bit short in leg so usually ride a small / medium frame, might even fit shorter 152mm / 160mm cranks. but also looking at a Specialized Epic M5 Comp FSR frame in good condition for £150.

Small Specialized from 30 or so years ago.

 

[2old]

@2old beautiful bike. you got the top end vintage specialized mtb there in an amazing color and good paint with simple fixed modern fork and fast tires. my hard rock is blushing. clean, this is similar to what i had in mind. Are you doing any regen? Do you have to adjust your riding for slower speeds to prevent overheating or just don't use the motor much those times?

@dgc you asking me or 2old? if me the mongoose atb is 21" and the hard rock ultra is 19". Neither is perfect for me on long drives but either will be acceptable once i've got the motor assisting. I love the maneuverability of the 19" but can get cramped on long hard rides and the atb geometry is just a little dated, i just need to raise the handlebars to cruise comfortably. I'll be higher than necessary but the view is nice up there

Thank you for your kind comment. No regen (don't want it) and no problem with overheating since the controller is exposed to lots of air turbulence. The bike hadn't been quite finished in the pic.